Optimization of electromagnetic wave absorption properties of Fe3O4/SBA-15

Fe₃O₄, possessing both dielectric and magnetic loss mechanisms, is an excellent microwave absorbing material. Nevertheless, the challenges posed by the poor impedance matching and narrow absorption bandwidth of pure Fe₃O₄ are significant. In this study, ordered mesoporous silica (SBA-15) was employed as a hard template, and Fe₃O₄/SBA-15 composites were synthesized through nano-impregnation. The results show that the impedance matching of the composites is effectively improved by increasing the content of SBA-15. In addition, the porous structure of SBA-15 extends the propagation distance of electromagnetic waves inside the material, thereby improving the microwave absorption performance of the composite material. Notably, when the molar ratio of Fe₃O₄ to SBA-15 is 10:13, the composite exhibits optimal microwave absorption properties, with a maximum reflection loss of − 35.21 dB and an effective absorption bandwidth of 5.44 GHz. Further analysis reveals that the microwave absorption performance of this composite primarily stems from the synergistic effect of dielectric and magnetic losses, including interfacial polarization, dipole polarization, and various ferromagnetic resonance loss mechanisms. This study provides new insights into the development of high-performance microwave absorbing materials.